Legrand - Pass & Seymour L630PCCV3 Industrial-Strength NEMA L6-30P Turnlok Locking Plug 30A, 250 Volt | Plugs IP20 Suitability, 3-Wire

If you're looking for an industrial style plug, they don't get any tougher than this. The plug is huge, roughly 2.5" in diameter, made of tough plastic. Even the strain relief is heavy duty. The two white pieces on the end come apart and are actually dovetailed to the plug body. They slide into dovetails and then screw together. Super tough. It's very easy to wire as there are no exposed screws you have to fit the wire under and then tighten and hope they don't come out. The plug has plastic channels that you feed the wire into and then tighten a setscrew. Easy to use and impossible for wires to short out b/c it's impossible for them to touch each other as each one goes into it's own channel. Worth every penny.

The plastic that this is made of feels very hefty and durable and the plug locks securely. I also appreciate that the internal connectors are completely isolated by plastic walls so there is no chance of a short circuit due to an errant strand on your wire.My one complaint is the threads on the screws. The threads work by biting directly into the plastic (like a wood screw, as opposed to a machine screw style thread), so after enough screwing and unscrewing the plastic will wear out, leaving nothing for the screw to attach to, thus limiting the re-usability of the plug.

Sturdy and well built. I used it to build a custom cable for my welder.It accepts 8 gauge wires, that’s the max size.

Pros:1. Good price2. Good quality, works wellCons:Screws are not the best quality and require just the right size slot head driver.

Works as should, great quality